Mitsubishi Galant (2004+). Manual - part 1185

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-433

STEP 10. Check harness connector B-23 at PCM for 
damage.

Q: Is the harness connector in good condition?

YES : Go to Step 11.
NO :  Repair or replace it. Refer to GROUP 00E, Harness 

Connector Inspection 

P.00E-2

. Then go to Step 15. 

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-434

STEP 11. Check for harness damage between left bank 
injector connector and PCM connector.

a. Check the harness wire between injector connector B-30 

(terminal No. 2) and PCM connector B-23 (terminal No. 
146) at No. 2 cylinder injector.

b. Check the harness wire between injector connector B-27 

(terminal No. 2) and PCM connector B-23 (terminal No. 
139) at No. 4 cylinder injector.

c. Check the harness wire between injector connector B-26 

(terminal No. 2) and PCM connector B-23 (terminal No. 
127) at No. 6 cylinder injector.

Q: Is the harness wire in good condition?

YES : Go to Step 12.
NO :  Repair it. Then go to Step 15.

STEP 12. Check the fuel pressure.

Refer to On-vehicle Service 

− Fuel Pressure Test 

P.13B-1133

.

Q: Is the fuel pressure normal?

YES : Repair it. Then go to Step 15.
NO :  Go to Step 13.

STEP 13. Check for entry of foreign matter (water, 
kerosene, etc.) into fuel.
Q: Are there any abnormalities?

YES : Replace the fuel. Then go to Step 15.
NO :  Go to Step 14.

AK303075

M

1

2

CONNECTOR: B-26, B-27, B-30

B-30 (GR)

B-27 (GR)

B-26 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

127 126 125 124 123 122 121

133 132 131 130 129 128

140 139 138 137 136 135 134

146 145 144 143 142 141

153 152 151 150 149 148 147

AK303058

HARNESS CONNECTOR: 
COMPONENT SIDE

CONNECTOR: B-23

B-23

PCM

AB

AIR CLEANER

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-435

STEP 14. Replace the left bank injector.

(1) Replace the left bank injector.
(2) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 2 − 

Fuel Trim Monitor 

P.13B-5

.

(3) Check the diagnostic trouble code (DTC).
Q: Is DTC P0174 set?

YES : Replace the PCM. Then go to Step 15.
NO :  The inspection is complete.

STEP 15. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to 

Diagnostic Function 

− OBD-II Drive Cycle − Procedure 2 − 

Fuel Trim Monitor 

P.13B-5

.

(2) Check the diagnostic trouble code (DTC).
Q: Is DTC P0174 set?

YES : Retry the troubleshooting.
NO :  The inspection is complete.

DTC P0175: System too Rich (bank 2)

CAUTION

If DTC P0175 has been set, TCL related DTC 
U1120 is also set. After P0175 has been diag-
nosed, don't forget to erase DTC U1120.

.

Fuel Trim Circuit

• Refer to DTC P0202− Injector Circuit − Cylinder 

2.

P.13B-482

, P0204

− Injector Circuit − Cylinder 

4.

P.13B-503

, P0206

− Injector Circuit − Cylinder 

6.

P.13B-524

. 

.

CIRCUIT OPERATION

• Refer to DTC P0202− Injector Circuit − Cylinder 

2.

P.13B-482

, P0204

− Injector Circuit − Cylinder 

4.

P.13B-503

, P0206

− Injector Circuit − Cylinder 

6.

P.13B-524

. 

.

TECHNICAL DESCRIPTION

• If a malfunction occurs in the fuel system, the fuel 

trim value becomes too small.

• The PCM checks whether the fuel trim value is 

within a specified range.

.

DESCRIPTIONS OF MONITOR METHODS
Left bank air/fuel learning value (long time fuel trim) 

and air/fuel feedback integral value (short time 
fuel trim) are too rich.

.

MONITOR EXECUTION
Continuous

.

MONITOR EXECUTION CONDITIONS (Other 
monitor and Sensor)

Other Monitor (There is no temporary DTC stored 

in memory for the item monitored below)

• Misfire monitor

Sensor (The sensor below is determined to be 

normal)

• Mass airflow sensor

• Engine coolant temperature sensor 

• Intake air temperature sensor

• Barometric pressure sensor

• Throttle position sensor

.

AK303075

M

1

2

CONNECTOR: B-26, B-27, B-30

B-30 (GR)

B-27 (GR)

B-26 (GR)

HARNESS CONNECTOR:
COMPONENT SIDE

AB

MULTIPORT FUEL INJECTION (MFI) DIAGNOSIS

TSB Revision

MULTIPORT FUEL INJECTION (MFI) <3.8L ENGINE>

13B-436

DTC SET CONDITIONS

Logic Flow Chart

.

Check Conditions

• Under the closed loop air/fuel ratio control.

• Engine coolant temperature is higher than 77°C 

(171

°F).

• Mass airflow sensor output is 8 g/sec or more.

Judgment Criteria

• Long-term fuel trim has continued to be lower 

than 

−12.5 percent for 5 seconds.

or

• Short-term fuel trim has continued to be lower 

than 

−7.4 percent for 5 seconds.

Check Conditions

• Under the closed loop air/fuel ratio control.

• Engine coolant temperature is higher than 77°C 

(171

°F).

• Mass airflow sensor output is 8 g/sec or less.

Judgment Criteria

• Long-term fuel trim has continued to be lower 

than 

−12.5 percent for 5 seconds.

or

• Short-term fuel trim has continued to be lower 

than 

−12.5 percent for 5 seconds.

K

LRN

: LONG-TERM TRIM

K

I

: SHORT-TERM TRIM

K0 : MAXIMUM LIMIT OF LONG-TERM TRIM
K1 : MAXIMUM LIMIT OF SHORT-TERM TRIM
K2 : MINIMUM LIMIT OF LONG-TERM TRIM
K3 : MINIMUM LIMIT OF SHORT-TERM TRIM

START

MONITORING

CONDITIONS

END

NO

NO

NO

NO

NO

NO

YES

YES

YES

YES

YES

YES

K

LRN

 > K0

MALFUNCTION

GOOD

K

LRN

 < K2

K

I

< K3

K

I

> K1

CONTINUOUS FAILURE

FOR 5secs

AK204050